JPH09136313A - Tendon fixing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a tendon from being damaged and to keep prescribed strength when tension is applied to the tendon. SOLUTION: In this apparatus, tendon 8 comprising FRP strips for reinforcing a structure of concrete, etc., are bundled and inserted into a cylindrical constraint member 14, the end sides are biased to be expanded to be separated from each other, tension is applied so that the ends are fixed by an anchor head 6 to keep the tension. The constraint member 14 is formed from a crystalline polymer such as MC nylon and ultra-high molecular weight polyethylene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension member fixing device for fixing a reinforcing tension member used in a structure such as prestressed concrete.

[0002]

2. Description of the Related Art The structure of a conventional tension member fixing device is shown in FIG. 4, and reference numeral 1 is a bearing plate provided so as to come into contact with a predetermined position of an end face of a concrete structure a.
The sheath 2 is attached to the inside of the. This sheath 2
The diameter of the end portion of the front end side of the drawing is narrowed as a narrowed portion 3, and a steel restraining member 4 formed in a cylindrical shape on the inner circumference of the narrowed portion 3.
Is fitted. FIG. 6 shows the appearance of the restraint member 4.

A lock nut 5 is provided on the outer surface of the pressure support plate 1, and an anchor head 6 as a fixing member is housed and fixed in the lock nut 5. As shown in FIG. 5, the anchor head 6 is provided with tapered holes 7 evenly at, for example, 6 positions on the same circumference.

Six tension members 8 corresponding to the tapered holes 7 are introduced into the sheath 2 through the inside of the restraining member 4 in the narrowed portion 3. The tension members 8 are constrained by the constraining member 4 so as to be focused in parallel.

A fixing sleeve 9 made of a metal such as aluminum is attached to an end of each tension member 8 introduced into the sheath 2. Then, each tension member 8 is deflected so as to spread out in a tapered shape after being inserted through the restraining member 4, and the sleeve 9 at the tip end side thereof is inserted into the taper hole 7 of the anchor head 6, respectively. Has been done. A split type fixing wedge 10 is fitted between the outer circumference of the sleeve 9 and the inner circumference of the tapered hole 7.

A graft injection port 2a is formed in a part of the peripheral surface of the sheath 2, and the other end of each tendon 8 has a concrete structure a on the opposite side of the bearing plate 1. It is locked at the end of.

In this state, a tensioning jack (not shown) is arranged on the outer surface side of the bearing plate 1, and the tensioning jack 8 holds the sleeve 9 of each tensioning member 8 and applies a tensile load to the tensioning member 8. And tension until a predetermined stretch is applied,
Under this tension state, each sleeve 9 is locked in the tapered hole 7 via the wedge 10, and the tension member 8 is fixed to the anchor head 6.

The respective tension members 8 are constrained so that the portions of the sheath 2 that are drawn out from the narrowed portion 3 to the outside thereof are closely arranged in parallel by a restraining member 4 provided in the narrowed portion 3, and restrained. The parts from the member 4 to the anchor head 6 are deflected so as to expand each other. Therefore, when a tension force is applied to each tension member 8, each tension member 8 strongly rubs against the inner circumference of the restraint member 4 due to the extension movement due to the tension, and further a local lateral pressure is applied from the restraint member 4. receive.

[0009]

Conventionally, wire rods made of steel have been used exclusively as a tension material, but in recent years, thermosetting fibers such as carbon fiber and aramid fiber having high strength and low elongation have been used. FRP filaments impregnated with a resin and cured have come into use.

In the case of a tension member made of such FRP filaments, if the restraining member is made of steel, the restraining member is FR.
Since the hardness is higher than that of the P-shaped wire, the outer layer of the tension member is damaged by rubbing due to the friction with the restraining member when the tension force is applied, and the tension member is damaged by the lateral pressure locally applied to the tension member. However, this causes a decrease in strength.

The present invention has been made paying attention to such a point, and an object thereof is to provide a tension member capable of preventing the tension member from being damaged when a tension force is applied and always maintaining the tension member at a predetermined strength. It is to provide a fixing device.

[0012]

In order to achieve such an object, the present invention has a tubular shape in which a plurality of tension members made of FRP linear filaments for reinforcing a structure such as concrete are bundled in parallel. A tension member fixing that inserts it into the restraining member, deflects the tip ends of the restraint member so as to expand each other, and applies a tension force to fix the end portion of the tip end side by the fixing member to maintain the tension state. In the device, the constraining member is formed of a crystalline polymer material such as MC nylon or ultra-high molecular weight polyethylene.

In the tension member fixing device having such a structure, when a tension force is applied to each tension member, even if each tension member strongly rubs against the inner circumference of the constraint member due to the extension movement caused by the tension, Unlike conventional steel, the material is a crystalline polymer material, so the restraining member deforms appropriately against the lateral pressure when the tension material is tensioned, the side pressure applied to the tension material is relieved, and the axis of the tension material is reduced. The direction slips better, and damage caused by rubbing when moving is reduced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. The same parts as those of the conventional structure are designated by the same reference numerals and the description thereof will be omitted. FIG. 1 shows a tension member fixing device of the present invention.
In this tension member fixing device, a cylindrical restraining member 14 made of a crystalline polymer material such as MC nylon is fitted on the inner circumference of the narrowed portion 3 of the sheath 2. And F
The ends of the tension members 8 made of RP-made filaments are fixed to the anchor head 6 via the sleeve 9, and the tension members 8 are brought into contact with the inner peripheral surface of the restraining member 14.

In such a structure, a tension force is applied to each tension member 8, and even if each tension member 8 strongly rubs against the inner circumference of the restraint member 14 due to the extension movement caused by the tension, the material of the restraint member 14 is increased. Unlike the conventional steel, since it is a crystalline polymer material such as MC nylon, the restraining member 14 is appropriately deformed against the lateral pressure when the tension member 8 is tensioned, and the lateral pressure applied to the tension member 8 is relaxed. In addition, the tension member 8 slides in the axial direction well, and damage caused by rubbing during its movement is reduced. As a result, the strength of the tension member 8 can be prevented from decreasing and the durability can be improved.

The following tests were conducted to confirm this effect. 2 and 3 show the test apparatus, in which 20 is a longitudinal member, and pressure bearing plates 21 and wedge-shaped anchor heads 2 are provided on the end faces of both ends of the longitudinal member 20, respectively.
2 is provided, and a pair of restraint members 14 are supported via a fixing jig 23 so as to be spaced apart from each other in the intermediate portion of the longitudinal member 20.

Between the bearing plates 21, six tension members 8 are provided.
Are stretched through the inside of each restraint member 14, both ends of these tension members 8 are respectively locked to the anchor heads 22, and these tension members 8 are arranged close to each other by the restraint member 14 in parallel. It has narrowed down.

The tendon 8 used in this test is an FRP filament made of carbon fiber and has a hardness of Shore D70 to 90,
The diameter is 12.5 mm, the design cutting load is 14.5 tf, and the total design cutting load of these 6 tendons is 87.0 tf. The restraint member 14 is formed in a tubular shape having an inner diameter of 60 mm.

In this state, the tensioning jacks 24 are arranged on the outer side surface of the one support plate 21, and the six tensioning members 8 are gripped by the tensioning jacks 24 to apply a load up to 65 tf.
Each tension member 8 is stretched and tensioned, and this tension state is set to 3
The tension / unloading test of unloading after maintaining for 3 minutes was repeated 3 times.

As the restraint member 14, a plurality of kinds of samples made of different materials were prepared, and the test was conducted for each sample made of a different material. The materials of the sample of the restraint member 14 are as shown in Table 1 below.

[0021]

[Table 1]

The results of the test conducted on each restraint member 14 are shown in Table 2 below. The tension side shown in this table means the restraint member 1 on the side close to the jack 24 when the tension member 8 is extended by the jack 24.
4 is the arrangement portion, and the fixed side is the arrangement portion of the restraint member 14 on the side away from the jack.

[0023]

[Table 2]

As shown in Table 2, with respect to the tension material, no scratches are formed on either the tension side or the fixed side even when the restraining member made of any material is used. For the restraint member, the material is urethane rubber,
Sample No.1-1,1 made of natural rubber and silicone rubber
In Nos. 2, 2, 5, 6, 6 and 7, surface scraping, edge crush marks, tears, and tear damage occurred, but sample No. 3 made of the crystalline polymer material targeted by the present invention In the restraint member made of ultra-high molecular weight polyethylene, a minute indentation with a depth of about 1 mm is on the tension side, and only a slightly visible indentation is generated on the fixed side.
In addition, the restraining member made of MC Nylon of No. 4 is the one on the tension side, and only slightly visible indentations are generated, and damage to the restraining member is reliably reduced.

In this experiment, the tension and unloading was repeated three times in consideration of the use as an unbonded type with re-tensioning, but in the case of a normal type tension material that does not require re-tensioning, it is more effective. The damage is even less.

As a means for fixing the tension member, a wedge type, a sleeve type, a screw type, an alloy socket type, or the like can be adopted, and the restraining member is also integrally formed into a cylindrical shape. In addition to the case where the strip-shaped material is formed into a cylindrical shape, the strip-shaped material may be rolled into a cylindrical shape.

[0027]

As described above, according to the present invention, since the restraining member that strongly rubs the tension member when the tension force is applied to the tension member is made of the crystalline polymer material, the tension when the tension force is applied is increased. It is possible to prevent damage to the timber and the restraining member and to always maintain the tendon at a predetermined strength.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tendon fixing device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a test device for applying tension / unloading to a tension member.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a cross-sectional view of a conventional tendon fixing device.

FIG. 5 is a front view of the tension member fixing device.

FIG. 6 is a perspective view showing the outer appearance of a restraint member.

[Explanation of Codes] a ... Concrete structure 4 ... Restraint member 6 ... Anchor head (fixing member) 8 ... Tension material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeyoshi Tanaka 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Within Taisei Corporation (72) Inventor Fumio Seki 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Inside Taisei Corporation (72) Inventor Manabu Hosoya 1-25-1 Nishishinjuku, Shinjuku-ku, Tokyo Inside Taisei Corporation

Claims (2)

[Claims] 1. A FRP for reinforcing a structure such as concrete.
A plurality of tension members made of wire-formed filaments are bundled in parallel and inserted into the cylindrical restraining member, and the tip ends of the tension members are deflected so as to expand each other, and a tension force is applied to the tip ends. A tension member fixing device for fixing an end portion of the sheet by a fixing member to maintain the tension state, wherein the restraining member is formed of a crystalline polymer material. 2. The tension member fixing device according to claim 1, wherein the crystalline polymer material which is the material of the restraint member is ultra-high molecular weight polyethylene or MC nylon.